These modulatory effects of low-dose tacrolimus on the expression and activation profiles of the Th1 (CD4+ IFNγ+)/Th2 (CD4+IL4+) and Th17 (CD4+IL17A+) Tregs have indeed been proven effective in the clinical management of women without PCOS but with recurrent implantation failure [129] and in a murine model of PCOS [128], respectively. Here, IL4 is linked to polycystic ovary syndrome.